Relax digitalWrite parameter check

[facchinm]

calling digitalWrite with any value different from 0 will end in performing digitalWrite(HIGH)
(to make it compatible with existing implementations for other cores)

[ArduinoBot]

✅ Build completed.

⬇️ Build URL: http://downloads.arduino.cc/PR/samd/package_samd-b25_index.json

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1. Open the Preferences of the Arduino IDE.
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3. Open the Boards Manager (menu Tools->Board->Board Manager...)
4. Install Arduino SAMD core - Pull Request Relax digitalWrite parameter check #26
5. Select one of the boards under SAMD Pull Request Relax digitalWrite parameter check #26 in Tools->Board menu
6. Compile/Upload as usual

[matthijskooijman]

Looks good to me. The only reason this would be bad if we ever want to support a third parameter to digitalWrite (like digitalWrite(HALF) or something unexpected like that), but I think that would break too many sketches out here to work), so no practical downsides to this change.

[aethaniel]

@facchinm, just for fun, this isn't matching the spec from https://www.arduino.cc/en/Reference/DigitalWrite

[matthijskooijman]

But it does match other implementations and, I think, user expectation. Perhaps this expectation should be solidified by updating the reference, though.

[aethaniel]

Indeed, the reference must be updated as it can be considered as the base spec for any new implementation. Well, it has been for me for the Due and Zero ports.

[cmaglie]

@aethaniel
to be precise, the new implementation match the specification exactly as the old one: the pin goes high when you pass HIGH and low when you pass LOW.

The specification leaves undefined all the other cases but the majority of implementations sets the pin high (I guess it's a consequence of the fact that in C/C++ 0 is considered false and everything else is true).